A typical rechargeable lithium-ion battery includes a negative electrode and a positive electrode separated by an electrolyte. Lithium ions move from the negative electrode through the electrolyte to the positive electrode during discharging and from the positive electrode through the electrolyte to the negative electrode during charging.
Cyclic charging/discharging degrades the electrodes and, in turn, can reduce the capacity of the battery. The mechanical and/or electrochemical mechanisms of degradation are not well understood and, as a result, models that have been developed for the estimation of battery health are based primarily on short-term empirical testing that is particular to a specific battery system. Although useful in some aspects, short-term empirical testing may be inaccurate and insufficient for mathematically modeling slow electrochemical processes over much longer periods.